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Premium Power Quality contracts and labeling

Webinar ECI 17 September 2007Work package 2 of the Quality of Supply and Regulation Project

Jasper van Casteren

Contents

• Introduction

• Power Quality contracts

• Power Quality classification

• Conclusions

Introduction

Important Power Quality dimensions:

• Continuous:- Slow voltage variation- Flicker severity- Harmonic distortion

• Events:- Voltage dips- Short interruptions

Introductionequipment

manufacturers

transmission /distributioncompanies

Customers

PQ

demandscomplains

PQ performanceemmission limits

producecompatibleequipment

specifylimits

standards &regulation

Introduction

Power Quality problems

• Great difference in Power Quality needed for different kind of customers

• Knowledge, common ground / understanding needed• Shared responsibility, due to interaction

Power Quality contracts

Benefits for the grid operator:• Customer-satisfaction.• Only investments into premium power quality for

customers who really need it.

Benefits for the customer:• Insured of a sufficient level of power quality.• A power quality solution in the grid could be cheaper

as a solution on site.

Power Quality contracts

• Financial mitigation instrument

• Minimum standards needed, to protect customers without a power quality contract for poor power quality.

• Good solution for customers which need high levels of power quality.

Examples of Power Quality contracts

• EdF, France• Autorità, Italy• Eskom, South-Africa• DEC, USA• UIC, USA• PSE&G, USA• Argentina

Power Quality contracts: France

• Both TNO (RTE) as well the biggest DNO (EdF).

• Contract called “Emeraude” (Emerald) and contains a “base-contract”, “contract with customer adjusted levels” and a “plus contract” for the most sensitive customers.

• Both demands on “delivered” voltage quality, as well on emission limits for customers.

Power Quality contracts: France

Requirements for voltage quality regarding.:

• Number of planned interruptions• Number of short and long planned interruptions• Number of voltage dips• Slow voltage variations• Rapid voltage fluctuations (flicker)• Unbalance• Frequency• Harmonic voltages

Power Quality contracts: Italy

• Voltage quality measurement campaign since 2006; Grid operators have to do power quality measurements at strategic locations in the grid and report to the regulator.

• The grid operator has to measure the voltage quality, on the customers requests. The customer paids the costs for it.

• Customers have the opportunity to participate in a power quality contract with the grid operator. Currently, no contracts have been established.

Power Quality contracts: Italy

At the moment 400 PQ meters at the MV rail of HV/MV stations and 200 PQ meters at customers.

The following voltage quality aspects need to be monitored and reported:

• Supply voltage variations• Supply voltage dips and peaks• Voltage interruptions• Voltage harmonics• Flicker• Supply voltage unbalance• Rapid voltage changes

Power Quality contracts: USA

• Detroit Edison Company (DEC) offers the “Special manufacturing Contract”.

• Developed for, and with, the automotive industry.

• In the beginning only for supply interruptions, in a later stage also for voltage dips, also depth is considered.

• “Sag Score” = 1-(Va+Vb+Vc)/3

Power Quality Argentina

• From 1992 a system with penalty payments in order to reduce the number of interruptions.

• From 1996 to 1998 a measuring program for voltage harmonics and flicker.

• After these 2 years also a system of penalty payments with minimum levels for voltage harmonics and flicker.

Summary of power quality contracts

• Most of the contracts are between utility and customers with sensitive processes and high costs.

• Most of the contracts concern reliability and voltage dips, however, other PQ aspects are measured.

• In most cases, the quality of supply has increasedIt isn’t the utilities aim to pay penalties.

• Relations between utility and customer become better.

Power Quality classification

• For customers without technical knowledge of power quality.

• Known from classification regarding energy efficiency.voltage

level

0.66

0.33

0.00

-0.33

-0.66

-1.00

1.00A

B

D

C

E

F

dips flicker

very high quality

high quality

poor quality

normal quality

very poor quality

extremely poor quality

Power Quality classification

)(

),,(),,( 1

q

pqvpqv l

mr −=

),,( pqvr

),,( pqvm

)(ql

• normalized PQ characteristic q, on site v, for phase p

• measured level of characteristic q, on site v, for phase p

• compatibility level of characteristic q

Power Quality classification: Flicker

( ) 52.0148.0

1,, =−=pqvr

A

B

D

C

EF

very high quality

high quality

poor quality

normal quality

very poor quality

extremely poor quality

95 % percentile flicker level

0.66

0.33

0.00

- 0.33

- 0.66

- 1.00

1.00 A

B

D

C

EF

very high quality

high quality

poor quality

normal quality

very poor quality

extremely poor quality

95 % percentile flicker level

0.66

0.33

0.00

- 0.33

- 0.66

- 1.00

1.00

Power Quality classification: Flicker

• Good way to check compliance with standard• Actual flicker levels are not visible, only extreme values• Different average flicker levels may lead to same

classification• To improve this, an other “performance indicator” must

be used.

Power Quality classificaton: Harmonics

• Each individual harmonic voltage and the THD can be classified on the same way as flicker.

• The worst classification letter, of the individual harmonics and THD, is ascribed to voltage harmonics.

Power Quality classification: Slow voltage variations

• Slow voltage variations can be classified with the STAV (Standard Deviation, Average Value)

V 3.2251 ==�

=

n

vU

n

ii

m

2

1

( )2.43

1

n

i mi

v UV

nσ =

−= =

−

�

Power Quality classification: Slow voltage variations

Power Quality classification: Slow voltage variations

100

90

80

70

60

50

30

40

20

10

0

500 ms. 10 s. 5 min.

S0

S1

S2

M0

M1

M2

L0

L1

L2

dip duration

rem

aini

ng v

olta

ge [

%]

20 ms.

Power Quality classification: Voltage dips

• Regions 0, 1 and 2• Dip types S, M and L

-

8

4

-

4

2

-

2

1

DIP classification

• Dip compatibility table– per dip type : max. average annual number of dips

“ABC” Classification of DIPS

• DIP compatibility table is used as limiting standard– specifies maximum allowed annual number of dips

• For each “ABC” classification, the DIP compatibility table is multiplied by 0/3, 1/3, 2/3, 3/3, 4/3, 5/3, 6/3

5/3 1/3

-11

5

-5

3

-3

1

-8

4

-4

2

-2

1

-3

1

-1

1

-1

0

-5

3

-3

1

-1

1

ABD CEF

-13

7

-7

3

-3

2

2/34/3

“ABC” Classification of DIPS

-

8

4

-

4

2

-2

1

-

1.7

5.2

-

3.4

10.3

-6.9

17.2

= 1.0⊗

* 0.01

DIP Severity

Normalized dip severity table– per dip type : average damage per dip– normalized : compatibility * costs = 1.0

Corresponding DIP performance indicator “CARCI”• compatibility table* normalized costs = 1.0• measured dip table * normalized costs = CARCI

• CARCI : Customer Average Rms voltage deviationCost Index

-6

3

-2

1

-1

0

= 0.50⊗

* 0.01-1.7

5.2

-3.4

10.3

-6.9

17.2

AB

DC

EF

very high quality

high quality

poor quality

normal quality

very poor quality

extremely poor quality

CARCI

0.66

0.33

0.00

-0.33

-0.66

-1.00

1.00

CARCI classification

CARCI = 0.50

“B”-

6

3

-2

1

-1

0

“C”

Advantages of DIP classification method• DIP cost table can be constructed for various types of

customer classes (industry, households, commercial, etc.)

• Specific CARCI can be calculated for individual customers

• Easy to be used for “what-if” dip mitigation questions

• Max. number of dips per dip type remain in place

Summary of classification

• Methods exist to calculate normalized levels of power quality performance

• These methods can be extended to other PQ-phenomena

• The color-coded “ABC” classification system is excellent for communicating the difficult subject of power quality to all customers in a meaningful and transparent way.

• DIP classification system clearly specifies responsibilities, useful for SLA’s.

Conclusions

• PQ contracts are attractive for customers with sensitive process and / or high costs due to poor power quality.

• Most contracts so far deal with the number of interruptions and voltage dips, however, other PQ aspects are measured.

• In most cases, the quality of supply has increasedIt isn’t the utilities aim to pay penalties.

• Relations between utility and customer become better.

• Power quality classification gives information about power quality for people without technical knowledge.

Experience you can trust.

The end

Thanks for your attention.

Jasper van Casteren+31 26 356 38 68

Jasper.vanCasteren@kema.com